Novel Polyhydroxybutyrate-Degrading Activity of the Microbulbifer Genus as Confirmed by Microbulbifer sp. SOL03 from the Marine Environment

( Sol Lee Park ),( Jang Yeon Cho ),( Su Hyun Kim ),( Hong-ju Lee ),( Sang Hyun Kim ),( Min Ju Suh ),( Sion Ham ),( Shashi Kant Bhatia ),( Ranjit Gurav ),( See-hyoung Park ),( Kyungmoon Park ),( Yun-go 한국미생물 · 생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.1

Ever since bioplastics were globally introduced to a wide range of industries, the disposal of used products made with bioplastics has become an issue inseparable from their application. Unlike petroleum-based plastics, bioplastics can be completely decomposed into water and carbon dioxide by microorganisms in a relatively short time, which is an advantage. However, there is little information on the specific degraders and accelerating factors for biodegradation. To elucidate a new strain for biodegrading poly-3-hydroxybutyrate (PHB), we screened out one PHB-degrading bacterium, Microbulbifer sp. SOL03, which is the first reported strain from the Microbulbifer genus to show PHB degradation activity, although Microbulbifer species are known to be complex carbohydrate degraders found in high-salt environments. In this study, we evaluated its biodegradability using solid- and liquid-based methods in addition to examining the changes in physical properties throughout the biodegradation process. Furthermore, we established the optimal conditions for biodegradation with respect to temperature, salt concentration, and additional carbon and nitrogen sources; accordingly, a temperature of 37℃ with the addition of 3% NaCl without additional carbon sources, was determined to be optimal. In summary, we found that Microbulbifer sp. SOL03 showed a PHB degradation yield of almost 97% after 10 days. To the best of our knowledge, this is the first study to investigate the potent bioplastic degradation activity of Microbulbifer sp., and we believe that it can contribute to the development of bioplastics from application to disposal.

Effects of Humidity on the Microstructure and the Ferroelectric Properties of Sol-Gel grown P(VDF-TrFE) Films

Young Joon Ko,진다운,Dae Sol Kong,Jong Hoon Jung 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.4

We report the microstructure and the ferroelectric properties of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] films grown under various humidity conditions and synthesis times by using a sol-gel method. When the synthesis time under a humid condition was short (approximately 30 min), the moisture in the environment affected only the surface morphology without any loss of ferroelectricity for the P(VDF-TrFE) films. In contrast, when the synthesis time was long (approximately 90 min), the moisture strongly affected the microstructure and the ferroelectric properties of P(VDF-TrFE). The transparent P(VDF-TrFE) film became opaque at high humidity. Scanning electron microscopy revealed numerous pores on the surface of and inside the film. The pores reduced the Young's modulus considerably from 4.15 to 0.97 GPa for the films grown at 20 and 80% relative humidity, respectively. In addition, the ferroelectric hysteresis loop disappeared at humidities above 60%. This work provides upper limits for the humidity and the synthesis time for the growth of high-quality P(VDF-TrFE) films by using a sol-gel method.

Adipic Acid Assisted Sol-Gel Synthesis of Li_1+x(Mn_0.4Ni_0.4Fe_0.2)_1-xO₂ (0 < x < 0.3) as Cathode Materials for Lithium Ion Batteries

Karthikeyan, Kaliyappan,Amaresh, Samuthirapandian,Son, Ju-Nam,Kim, Shin-Ho,Kim, Min-Chul,Kim, Kwang-Jin,Lee, Sol-Nip,Lee, Yun-Sung Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.1

Layered $Li_{1+x}(Mn_{0.4}Ni_{0.4}Fe_{0.2})_{1-x}O_2$ (0 < x < 0.3) solid solutions were synthesized using solgel method with adipic acid as chelating agent. Structural and electrochemical properties of the prepared powders were examined by means of X-ray diffraction, Scanning electron microscopy and galvanostatic charge/discharge cycling. All powders had a phase-pure layered structure with $R\bar{3}m$ space group. The morphological studies confirmed that the size of the particles increased at higher x content. The charge-discharge profiles of the solid solution against lithium using 1 M $LiPF_6$ in EC/DMC as electrolyte revealed that the discharge capacity increases with increasing lithium content at the 3a sites. Among the cells, $Li_{1.2}(Mn_{0.32}Ni_{0.32}Fe_{0.16})O_2$ (x = 0.2)/$Li^+$ exhibits a good electrochemical property with maximum initial capacity of 160 $mAhg^{-1}$ between 2-4.5 V at 0.1 $mAcm^{-2}$ current density and the capacity retention after 25 cycles was 92%. Whereas, the cell fabricated with x = 0.3 sample showed continuous capacity fading due to the formation of spinel like structure during the subsequent cycling. The preparation of solid solutions based on $LiNiO_2-LiFeO_2-Li_2MnO_3$ has improved the properties of its end members.

Adipic Acid Assisted Sol-Gel Synthesis of Li1+x(Mn0.4Ni0.4Fe0.2)1-xO2 (0 < x < 0.3) as Cathode Materials for Lithium Ion Batteries

Kaliyappan Karthikeyan,Samuthirapandian Amaresh,Ju-Nam Son,Shin-Ho Kim,Min-Chul Kim,김광진,이윤성,Sol-Nip Lee 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.1

Layered Li1+x(Mn0.4Ni0.4Fe0.2)1-xO2 (0 < x < 0.3) solid solutions were synthesized using solgel method with adipic acid as chelating agent. Structural and electrochemical properties of the prepared powders were examined by means of X-ray diffraction, Scanning electron microscopy and galvanostatic charge/discharge cycling. All powders had a phase-pure layered structure with R3m space group. The morphological studies confirmed that the size of the particles increased at higher x content. The charge-discharge profiles of the solid solution against lithium using 1 M LiPF6 in EC/DMC as electrolyte revealed that the discharge capacity increases with increasing lithium content at the 3a sites. Among the cells, Li1.2(Mn0.32Ni0.32Fe0.16)O2 (x = 0.2)/ Li+ exhibits a good electrochemical property with maximum initial capacity of 160 mAhg−1 between 2-4.5 V at 0.1 mAcm−2 current density and the capacity retention after 25 cycles was 92%. Whereas, the cell fabricated with x = 0.3 sample showed continuous capacity fading due to the formation of spinel like structure during the subsequent cycling. The preparation of solid solutions based on LiNiO2-LiFeO2-Li2MnO3 has improved the properties of its end members.

초등 문학교육에서 내면화 활동의 개선 방향 - 2015 개정 국어 교과서를 중심으로 -

진솔 ( Jin¸ Sol ) 청람어문교육학회 2021 청람어문교육 Vol.- No.83

본고는 초등 문학교육에서 다뤄지는 내면화의 의미를 고찰하고 내면화 활동의 양상을 비판적으로 살폈으며 개선 방향을 제안하였다. 문학교육에서 학습자는 작품 속 가치를 이미 존재하는 것으로서 수용하기보다는, 능동적인 태도로 작품과의 상호작용을 통해 적극적으로 가치를 내면화할 필요가 있다. 따라서 내면화는 비판과 상상의 작용을 통한 반성 작용으로서 의미화할 수 있다. 이론적 고찰을 토대로 실제 2015 개정 국어 교과서에는 내면화를 위한 활동이 어떻게 구현되었는지를 살폈다. 이를 바탕으로 한 내면화 활동의 개선 방향은 첫째, 문학 작품에 기반한 독자 경험을 활성화할 필요가 있다. 둘째, 인물의 말과 행동을 유기적으로 연결 지어 종합적 맥락을 파악해야 한다. 셋째, 서사적 상상력을 발현할 필요가 있다. 이와 관련하여 학습자의 적극적 표현 활동이 가치의 내면화를 위해 필요하다. This paper examines the meaning of internalization in elementary school literature education, critically examines the aspects of internalization activities, and suggests directions for improvement. In literary education, learners need to actively internalize values through interaction with works in an active attitude, rather than accepting the values in works as already existing ones. Therefore, internalization can be understood as a reflection action through the action of criticism and imagination. Based on theoretical considerations, we examined how the activities for internalization were implemented in the actual 2015 revised Korean textbook. To improve the internalization activity based on this, first, it is necessary to activate the reader's experience based on literary works. Second, it is necessary to organically connect the words and actions of the characters to understand the overall context. Third, it is necessary to express narrative imagination. In this regard, active expression activities of learners are necessary for internalization of values.

Proton-irradiated Pb(Zr_0.52Ti_0.48)O₃ thick films for flexible non-volatile memory applications

Lee, Tae Kwon,Kong, Dae Sol,Jin, Da Woon,Yun, Shinhee,Yang, Chan-Ho,Jung, Jong Hoon ELSEVIER 2019 Current Applied Physics Vol.19 No.6

<P><B>Abstract</B></P> <P>We investigated the ferroelectricity in proton-irradiated flexible Pb(Zr<SUB>0.52</SUB>Ti<SUB>0.48</SUB>)O<SUB>3</SUB> (PZT) thick films and their non-volatile memory characteristics. The Ni-Cr metal foil substrate allowed high-quality polycrystalline PZT films with flexible functionality to be fabricated using conventional sol-gel and high-temperature annealing methods. The 10-MeV proton-irradiated PZT film exhibited an almost square polarization−electric field hysteresis curve with saturated (<I>P</I> <SUB>s</SUB>) and remnant (<I>P</I> <SUB> <I>r</I> </SUB>) polarizations of 18.9 and 17.0 μC/cm<SUP>2</SUP>, respectively; which are slightly lower than as-grown PZT with <I>P</I> <SUB>s</SUB> = 28.7 μC/cm<SUP>2</SUP> and <I>P</I> <SUB> <I>r</I> </SUB> = 24.3 μC/cm<SUP>2</SUP>. The <I>P</I> <SUB> <I>r</I> </SUB> did not decrease even after 1000 cycles of continuous bending and unbending at a bending radius of 2.14 mm and decreased slightly to ∼80% of its initial value after 10<SUP>5</SUP> s. Although the <I>P</I> <SUB> <I>r</I> </SUB> decreased to ∼55% after 10<SUP>10</SUP> cycles, the electric polarization remained switchable under positive and negative electric fields. These characteristics suggest that the flexible PZT films could be utilized in non-volatile memory device applications in environments with high doses of proton irradiation, such as those in aeronautics and nuclear power plants.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sol-gel growth of flexible PZT thick films on a Ni-Cr metal foil substrate. </LI> <LI> Large saturated and remnant electric polarization in proton-irradiated films. </LI> <LI> Mechanical stability, long retention time, and high fatigue resistance even after the high energy proton-irradiation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

ASR for EFL Pronunciation Practice: Segmental Development and Learners’ Beliefs

Solène Inceoglu,Hyojung Lim,Wen-Hsin Chen 아시아영어교육학회 2020 The Journal of Asia TEFL Vol.17 No.3

The current study explored the usefulness of mobile-based automatic speech recognition (ASR) pronunciation practice by investigating a) its effects on the production of four English vowels, and b) learners’ perception of ASR as a learning tool. A total of 19 Korean university students produced 28 minimal pair sentences containing the English vowel contrasts /i/-/ɪ/ and /ɛ/-/æ/ (e.g., I said beat, I said bit) at pretest and posttest, and completed six sessions of ASR practice outside of class that involved voice-typing a short text, minimal pairs in sentences, and decontextualized minimal pairs. Results of acoustic analysis of F1 and F2 formant frequencies showed a meaningful improvement in frontness for the vowel /i/, but no changes for the other vowels. Overall, the majority of the participants perceived ASR as useful for pronunciation practice, but some showed skepticism and frustration regarding the current state of the technology. Further discussed are the problems and limitations that EFL learners experienced during the ASR training.

A Gain Adaptive Strategy to Improve Closed-loop Performance of Robust Asymptotic Feedback Linearization

Gualberto Solís-Perales,Jairo Sánchez-Estrada,Ricardo Femat 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.9

This contribution presents a gain adaptation, which allows us to tune a robust asymptotic feedback linearization (RAFL). The gain adaptation allows the RAFL to attenuate the measurement noise sensitivity. The RAFL is considered here because it ensures tracking without prior information about the system’s nonlinearities and parameter bounds. Also, the RAFL only has the system output available for feedback. In this work, the robust tracking problem is faced considering: modeling errors, parametric variations, external perturbations, and noisy output measurement. On one side, the RAFL control faces modeling errors, parametric variations, and external perturbations through an observer that estimates uncertainties using an extra state, which lumps all the unknown nonlinearities and uncertainties. On the other hand, the proposed adaptive gain function allows the observer’s high gain to vary to have a fast observer’s convergence while simultaneously avoiding amplifying the measurement noise in the steadystate. The adaptive gain function provides the RAFL control robustness against noisy measurement. Thereby, the RAFL control with adaptive gain function becomes a robust feedback linearizing against to measurement noise. Finally, the RAFL controller with the adaptive gain function is illustrated by a numerical simulation of a tracking problem for a DC-motor and a chemical oxygen demand regulation in an anaerobic digestion process.

Activation of Neuronal Ensembles via Controlled Synchronization

Gualberto Solís-Perales,Juan Gonzalo Barajas-Ramírez 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.1

In this contribution we present the activation of neuronal ensembles of Hindmarsh-Rose neurons bycontrolled synchronization. The main problem consists in to impose a particular spiking-bursting behavior in allthe neurons of the network. We consider a network where the neurons are in its resting state, it is desired that theneurons change their resting state to a particular behavior of activation, dictated by a neuron called the referenceneuron. The goal is reached by controlling some neurons in the network controlling only the membrane potential(electrical synapse). The key feature of the present contribution is that by controlling a small number of neuronsin the network a desired behavior is induced in all the neurons in the network despite its network topology. Theimportant parameters are the control gain and the coupling strength, thus the activation of the network lays downon a compromise between the control gain and the coupling strength.

The Trans-Pacific Partnership: Can the United States Lead the Way in Asia–Pacific Integration?

Mireya Solís 인하대학교 국제관계연구소 2012 Pacific Focus Vol.27 No.3

Abstract: High stakes are involved in the Trans-Pacific Partnership (TPP) trade negotiations:the United States seems to be on the verge of redirecting Asian regionalism towards an Asia–Pacific trade grouping that proclaims will not tolerate sectoral exclusions and will tackle head on non-tariff barriers (long considered glaring deficiencies of most free trade agreements). However, US domestic politics may prevent the realization of these lofty objectives. The influence of internal political constraints is evident in three areas: (i) the United States has pushed for a hybrid approach on market access negotiations that clouds the prospects of TPP adhering to the no-carve-out mantra;(ii) US trade negotiators have ramped up their negotiation objectives into a so-called platinum standard that could impose heavy preconditions on accession for new members and diminish the chances of growing the TPP membership; and (iii) the protracted ratification process and lack of trade promotion authority undermines the credibility of the United States in the eyes of prospective trade partners.